Polycarbonates are polymers that may be derived from bisphenols and phosgene, or their derivatives. They are useful for forming a wide variety of products, such as by molding, extrusion, and thermoforming processes. Such products include articles and components that include auto parts, electronic appliances and cell phone components. Because of their broad use, particularly in electronic applications and auto part applications, the desired properties of polycarbonates include high impact strength and toughness, heat resistance, weather and ozone resistance, and good ductility. It is also desirable that polycarbonates exhibit physical properties amenable to efficient and economic manufacturing processes.
Certain indane bisphenol monomers, such as 4,4′-(2,3-dihydro-1H-indene-1,1-diyl)diphenol, have been used to prepare high heat polycarbonates. Such indane bisphenols are, however, prone to chemical reaction at the benzylic position (e.g., deprotonation or oxidation), which in turn adversely impacts the properties and functional lifetime of the polycarbonates derived therefrom.
Indanone bisphenols, such as 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one, lack benzylic hydrogens, and as a result avoid the stability issues of indane bisphenols such as 4,4′-(2,3-dihydro-1H-indene-1,1-diyl)diphenol. Consequently, indanone bisphenols have largely replaced indane bisphenols as the preferred monomer type to impart high heat resistance to polycarbonates.
Nonetheless, there still exists a need for improved monomers and polycarbonates, and high heat polycarbonates in particular, demonstrating one or more of acceptable impact strength, heat resistance, weatherability, ductility, and processability.